Instead of a rumour that German physicists are working on the bomb, a rumour occurs that they’re working on a pact. You are the equivalent of the Manhattan project, but you’re trying to create a magical superweapon. Your campaign: beat the Germans to the wish spell.
Start the whole team on magic classes, and have them chase after rumours in a 1940 WW2 setting.
I always wanted to play a PvP game where players create a magical weapon for a city and their enemy send other players to destroy it.
It could be so strategic and fun to play. You could see the players torn apart between what the have to do and their convictions.